How do the global warming potentials of isobutane compare to other additives? Used as an additive, isobutane is quickly gaining attention.
Isobutane is essentially a liquefied gas, and like many others, it also has the potential to contribute to global warming.
But the question is, “how do the global warming potentials of isobutane r600a propane compare to others?”
Let’s find out now!
Global warming potential (GWP) is on the lower side for isobutane r600a as compared to many other similar gases and refrigerants.
How Do the Global Warming Potentials of Isobutane Compare to Others?
Today, you can find various liquefied gasses as well as additives, but they all have an impact on global warming.
Where isobutane stands in terms of its global warming potential is an important consideration.
But before learning more about that, let’s learn a bit more about this liquefied gas first:
What is Isobutane and Why is It Called That?
Isobutane, R600A, also known as i-butane, is a liquefied gas that has been treated and hydrogenated to achieve a high degree of purity.
- It is used in the food industry as an additive E-934b.
- It is used as a refrigerant for keeping food cool.
- It is also a propellant used in aerosols.
- It is used widely in the manufacturing of polyethylene (polythene), typically for single use.
More about the Chemistry of Isobutane
This colorless hydrocarbon, isobutane, is one of two butane isomers, hence iso – butane.
They share the same atomic makeup and R600A has traces of butane’s petroleum-like odor.
It is highly flammable, igniting easily, sometimes spontaneously and violently.
That is especially the case when left exposed to heat which makes it a reliable cheap fuel for mass-produced disposable lighters.
Fact: As a vapor, isobutane sinks to the ground displacing the air causing asphyxiation, but as a liquid it causes frostbite.
What is the Global Warming Potential of Isobutane?
Like many gases, isobutane has a value determined by its global warming potential, GWP.
It is a comparative measure of how much energy the emission absorbs per ton relative to the emissions of a ton of carbon dioxide.
As a system, it standardizes the method for establishing the potential impact of greenhouses (GHGs) on the planet.
It is part of global reporting system so the value serves to clarify communication by providing all involved in the study of gases and their impact shared reference points.
An Important Consideration
The GWP value is a calculated measure of how much infrared radiation a particular greenhouse gas added to the atmosphere would absorb over a specified time.
But realistically, the value only offers a good estimate of a gas’s impact because conditions in the atmosphere fluctuate.
Calculation and Comparison of GWPs of Different Greenhouse Gases
The impact of GHGs on the atmosphere is better understood almost daily and so GWP values are reviewed constantly.
Therefore, the values form an index to find innumerable gaseous compounds’ GWP.
For instance:
| Substance | GWP Value |
| CO2 | 1 |
| HCFC-22 (R-22) | 1760 |
| HFC-152a | 124 |
| HCFC-124 | 609 |
All are blended mixtures of gases.
To find their combined GWP the GWP value of each separate component was added together in proportion to the overall mass.
How are the Global Warming Potentials of Isobutanes Measured?
Three factors determine the GWP of isobutanes:
- how well-infrared radiation is absorbed,
- The projection’s timescale
- how long it takes the gas to leave the atmosphere, and its atmospheric lifetime.
Generally, a high value would indicate strong absorption over a long atmospheric lifetime. And this is compared to the absorption rate and lifetime of carbon dioxide, the baseline.
However, determining just how well R600A, a natural refrigerant, is absorbing radiation in the atmosphere is not clear cut.
The gas could be at a location where there is little radiation to absorb over the timescale or it is being absorbed by other compounds in that particular area of the atmosphere.
The timescale could be too long or too short.
Fact: The recent advances in infrared spectroscopy have made observing the invisible infrared spectrum and its wavelengths easier and they can be correlated to its GWP.
Is the Global Warming Potential of Isobutane High or Low?
Isobutane is one of the hydrocarbon family of gases which only contain hydrogen and carbon.
Each family member has the same number of atoms but they are arranged slightly differently. They share familial characteristics, like their distinctive aroma.
The other common gas in the family is propane and both have a GWP of three, a very low global warming potential compared to some other refrigerants.
They also share a zero on another scale, the ODP. On this scale the values refer to the ozone depletion potential of chemical compounds.
The values represent the level of damage to the ozone layer each compound has the potential to cause compared to CFC-11, trichlorofluoromethane which has an ODP value of 1.
Fact: The production of and use of all CFC has either been banned or phased out globally under the Montreal Protocol.
The Comparison of R-600a with Other Substances
Here is a bit of information to help you have a good idea about the comparison of R-600 with other refrigerants:
| Refrigerant | Description | GWP Value |
| R-441A | The replacement for HFC-134A is an ethane-propane-butane-isobutane hydrocarbon refrigerant blend. | 0 |
| HFC-134A | Tetrafluoroethene was a common refrigerant in the ’90s. | 1300 |
| R-404A | Historically widespread usage of a nonflammable refrigerant blend | 3922 |
| R-410A | Another refrigerant used in cooling systems besides R-404A. | 1890 |
Factors affecting the GWP of Isobutane
Isobutane, with its low GWP of 3 is an efficient natural refrigerant.
It is now the preferred environmentally friendly option with diverse domestic, commercial, and industrial applications and there is worldwide demand for gas and others like it.
Ozone damage due to R-600A is almost negligible compared to any of the manufactured alternatives. R-600A is versatile.
Isobutane mixes with other natural refrigerants very well.
The main factor affecting its GWP is how the measurement is calculated, over 100 years when the gas itself has a short atmospheric lifetime.
Fact: The R-600a is relatively stable but the only significant disadvantage is its high flammability.
Emissions and Sources of Isobutane and Effects on GWP
The butane used to process isobutane comes from natural gas, a fossil fuel. Its abundant and cheap and easy to refine.
Although isobutane is more expensive, its tertiary structure means it makes up for its versatility.
Its emissions stay low despite how it is used. And because it mixes well with other compounds, it has many uses.
Its biggest market, about 85% of production, is for a process called alkylation, used in refining high-octane fuel to reduce its emissions.
Its growing global use has the potential to lower the GWP of a great many compounds.
Atmospheric Lifetime of Isobutane and Effects on GWP
Isobutane is a safe refrigerant with a short atmospheric lifetime. It takes about a year for the atmosphere to return to its pre-isobutane equilibrium.
Other natural hydrocarbons’ atmospheric lifetimes can be as short as a few weeks or days.
Such short-lived compounds do not easily suit measurements calculated using the 100-year window, GWP100.
Although this timescale has become the standard in the US, there are some who dispute the values of the GWP scale because of it and argue there’s a political motive involved.
Fact: In places where the climate change priorities are perhaps more pressing, researchers modeling using GWP10 or GWP20 claim the shorter timescale scenario is more realistic.
Need for Further Research on Isobutane’s GWP
There is always a lively debate surrounding which is the most appropriate mathematical method to use when calculating global warming potential.
And it is indicative of the advances made overall in climate research.
There has been massive investment in the breadth of study, technology and equipment to enable us to better understand the damage we inflict on the atmosphere.
Modeling suggests that if we had used more isobutane sooner, the dramatic change in the climate we are facing wouldn’t exist.
Although isobutane seems something of a wonder chemical, it is still a hydrocarbon that doesn’t occur naturally in the atmosphere and that calls for continuing research.
Takeaway
How do the global warming potentials of isobutane compare to other gases and refrigerants? There has been a lot of talk about the benefits of using isobutane.
But, at the same time, there are controversies surrounding the methods used to measure its global warming potential, which is considered quite low.
It definitely looks promising, but at the end of the day, it is a hydrocarbon and warrants more research.
